"I'm terribly concerned, no question about it," [Mets manager] Jerry Manuel said Monday. "He's been pitching probably since the break (with soreness), but not to the level of discomfort he has now."

In Santana's place, the Mets will start Nelson Figueroa Tuesday.

"I know that he's a gamer and he wants to be out there with his teammates and fight through all the adversity that this team has had to go through," said [Mets reliever] Billy Wagner (who just returned from Tommy John surgery). "But I think if he tries to push it, and possibly injures himself worse, he's talking about his career. He's not talking about just one season."

On the season, Santana is 13-9 with an ERA of 3.13 and 146 strikeouts.